Viburnum leaf beetles are chewing susceptible bushes into skeletal remains in central, western and northern New York state. The beetles, which face few predators, now appear to be taking aim at western New England and parts of Pennsylvania, and they are poised to move into the Hudson Valley, the New York City metropolitan area and Long Island.

To locate the beetles, Cornell University researchers have started the Viburnum Leaf Beetle Citizen-Scientist Project. They are asking home gardeners, landscapers, 4-H groups and schoolchildren to become volunteer "citizen scientists" to scout for the invasive pest beginning in late April.

"We can use all the help we can get to follow the rapid spread of the beetle," says Lori Bushway, Cornell senior extension associate in horticulture. "And citizens can help us to understand the life-cycle patterns of this beetle, as well as simple things such as how the weather affects the insect's stages. We are excited about this project because it involves ordinary citizens in gathering valuable information. Ultimately that can help keep this pest from ravaging our landscapes."

Bushway says that no expertise in horticulture or entomology is needed to participate in the project. "Even if you've never heard of this pest before, we can show you how to identify it," she says.

At the heart of the project is a Web site, http://www.hort.cornell.edu/VLB , providing detailed pictures that make it easy to identify the beetle and the viburnum bushes it attacks. Citizen-scientists can register at the site and use online forms to report sightings and other observations.

E. Richard Hoebeke, Cornell assistant curator of the entomology collection, first found the beetle in New York on July 5, 1996, at Fair Haven Beach State Park in northern Cayuga County along the Lake Ontario shore. That summer he also found the pest in Monroe, Orleans, Niagara and Jefferson counties. The counties of St. Lawrence, Oswego, Ontario, Wayne and Genesee have since joined the growing list. Now the pest has spread through New York's Finger Lakes region and the Southern Tier.

First discovered in Canada in 1947, the viburnum leaf beetle is believed to have traveled from Europe on nursery plants around the turn of the 20th century, according to Hoebeke. It was not seen in North America again until 1955 at Font Hill, Ontario. The insect then went undetected for 23 years, until it was found again in Ottawa, Ontario, and neighboring Hull, Quebec.

The adult beetles (Pyrrhalta viburni) are hard to see, resembling a small, dark-brown blotch about the size of the head of a large matchstick. The young larvae have an off-white color, and in the second larval stage they develop black, uniform spots on their backs. Both larvae and adults are devastating to the ornamental plants.

An adult female can lay up to 500 eggs, and the larvae hatch in late April or early May. They feed on the viburnum leaves throughout the larval period, which lasts four to five weeks. By early to mid-July, the adults appear and continue gorging on the remaining leaves. They then mate and lay eggs on the shrub's twigs.

"The larvae are voracious eaters and can completely defoliate a virburnum," says Paul Weston, Cornell senior research associate in entomology and a project team member. "Later in summer the adults can come back and strip the plants bare again. Repeated defoliation over several years can weaken and kill a viburnum bush," he says.

For information on participating in the Viburnum Leaf Beetle Citizen-Scientist Project, contact Bushway at ljb7@cornell.edu or (607) 255-5918.